Oracle PL/SQL/Trigger/Before Trigger
Create a Before Row Trigger
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SQL> CREATE TABLE EMP(
2 EMPNO NUMBER(4) NOT NULL, 3 ENAME VARCHAR2(10), 4 JOB VARCHAR2(9), 5 MGR NUMBER(4), 6 HIREDATE DATE, 7 SAL NUMBER(7, 2), 8 COMM NUMBER(7, 2), 9 DEPTNO NUMBER(2) 10 );
Table created.
SQL> INSERT INTO EMP VALUES(2, "Jack", "Tester", 6,TO_DATE("20-FEB-1981", "DD-MON-YYYY"), 1600, 300, 30); 1 row created. SQL> INSERT INTO EMP VALUES(3, "Wil", "Tester", 6,TO_DATE("22-FEB-1981", "DD-MON-YYYY"), 1250, 500, 30); 1 row created. SQL> INSERT INTO EMP VALUES(4, "Jane", "Designer", 9,TO_DATE("2-APR-1981", "DD-MON-YYYY"), 2975, NULL, 20); 1 row created. SQL> INSERT INTO EMP VALUES(5, "Mary", "Tester", 6,TO_DATE("28-SEP-1981", "DD-MON-YYYY"), 1250, 1400, 30); 1 row created. SQL> INSERT INTO EMP VALUES(6, "Black", "Designer", 9,TO_DATE("1-MAY-1981", "DD-MON-YYYY"), 2850, NULL, 30); 1 row created. SQL> INSERT INTO EMP VALUES(7, "Chris", "Designer", 9,TO_DATE("9-JUN-1981", "DD-MON-YYYY"), 2450, NULL, 10); 1 row created. SQL> INSERT INTO EMP VALUES(8, "Smart", "Helper", 4,TO_DATE("09-DEC-1982", "DD-MON-YYYY"), 3000, NULL, 20); 1 row created. SQL> INSERT INTO EMP VALUES(9, "Peter", "Manager", NULL,TO_DATE("17-NOV-1981", "DD-MON-YYYY"), 5000, NULL, 10); 1 row created. SQL> INSERT INTO EMP VALUES(10, "Take", "Tester", 6,TO_DATE("8-SEP-1981", "DD-MON-YYYY"), 1500, 0, 30); 1 row created.
SQL> INSERT INTO EMP VALUES(13, "Fake", "Helper", 4,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 3000, NULL, 20); 1 row created.
SQL> SQL> SQL> create or replace trigger emp_br before insert or update or delete
2 on emp
3 for each row
4 begin
5 dbms_output.put_line("...before row (emp)");
6 end;
7 /
Trigger created. SQL> SQL> drop table emp; Table dropped.
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Create a Before Statement trigger
<source lang="sql">
SQL> CREATE TABLE DEPT(
2 DEPTNO NUMBER(2), 3 DNAME VARCHAR2(14), 4 LOC VARCHAR2(13) 5 );
Table created. SQL> SQL> INSERT INTO DEPT VALUES (10, "ACCOUNTING", "NEW YORK"); 1 row created. SQL> INSERT INTO DEPT VALUES (20, "RESEARCH", "DALLAS"); 1 row created. SQL> INSERT INTO DEPT VALUES (30, "SALES", "CHICAGO"); 1 row created. SQL> INSERT INTO DEPT VALUES (40, "OPERATIONS", "BOSTON"); 1 row created. SQL> SQL> SQL> create or replace trigger deptbs before insert or update or delete
2 on dept
3 begin
4 dbms_output.put_line("before statement (dept)");
5 end;
6 /
Trigger created. SQL> SQL> drop table dept; Table dropped.
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Define trigger brefore all updataction actions
<source lang="sql">
SQL> -- create demo table SQL> create table Employee(
2 ID VARCHAR2(4 BYTE) NOT NULL, 3 First_Name VARCHAR2(10 BYTE), 4 Last_Name VARCHAR2(10 BYTE), 5 Start_Date DATE, 6 End_Date DATE, 7 Salary Number(8,2), 8 City VARCHAR2(10 BYTE), 9 Description VARCHAR2(15 BYTE) 10 ) 11 /
SQL> SQL> -- prepare data SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values ("01","Jason", "Martin", to_date("19960725","YYYYMMDD"), to_date("20060725","YYYYMMDD"), 1234.56, "Toronto", "Programmer")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("02","Alison", "Mathews", to_date("19760321","YYYYMMDD"), to_date("19860221","YYYYMMDD"), 6661.78, "Vancouver","Tester")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("03","James", "Smith", to_date("19781212","YYYYMMDD"), to_date("19900315","YYYYMMDD"), 6544.78, "Vancouver","Tester")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("04","Celia", "Rice", to_date("19821024","YYYYMMDD"), to_date("19990421","YYYYMMDD"), 2344.78, "Vancouver","Manager")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("05","Robert", "Black", to_date("19840115","YYYYMMDD"), to_date("19980808","YYYYMMDD"), 2334.78, "Vancouver","Tester")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("06","Linda", "Green", to_date("19870730","YYYYMMDD"), to_date("19960104","YYYYMMDD"), 4322.78,"New York", "Tester")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("07","David", "Larry", to_date("19901231","YYYYMMDD"), to_date("19980212","YYYYMMDD"), 7897.78,"New York", "Manager")
3 /
SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("08","James", "Cat", to_date("19960917","YYYYMMDD"), to_date("20020415","YYYYMMDD"), 1232.78,"Vancouver", "Tester")
3 /
SQL> SQL> SQL> SQL> -- display data in the table SQL> select * from Employee
2 /
ID FIRST_NAME LAST_NAME START_DAT END_DATE SALARY CITY DESCRIPTION
---------- ---------- --------- --------- ---------- ---------- ---------------
01 Jason Martin 25-JUL-96 25-JUL-06 1234.56 Toronto Programmer 02 Alison Mathews 21-MAR-76 21-FEB-86 6661.78 Vancouver Tester 03 James Smith 12-DEC-78 15-MAR-90 6544.78 Vancouver Tester 04 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver Manager 05 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver Tester 06 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York Tester 07 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager 08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester SQL> SQL> SQL> create table employees_copy as select * from employee; SQL> SQL> create table employees_log(
2 who varchar2(30), 3 when date );
SQL> SQL> create trigger biud_employees_copy
2 before insert or update or delete 3 on employees_copy 4 begin 5 insert into employees_log( who, when ) 6 values( user, sysdate ); 7 end; 8 /
SQL> SQL> update employees_copy set salary = salary * 1.1; SQL> SQL> select * from employees_log; WHO WHEN
---------
sqle 09-SEP-06 SQL> SQL> delete from employees_copy; SQL> SQL> select * from employees_log; WHO WHEN
---------
sqle 09-SEP-06 sqle 09-SEP-06 SQL> SQL> drop table employees_log; SQL> SQL> drop table employees_copy; SQL> SQL> -- clean the table SQL> drop table Employee
2 /
SQL> SQL>
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